Automatic loader bucket control and indicator



United States Patent [72] lnventors Herbert W. Borer Naperville; John R. Muntjanofl, Aurora, Ill. [21] Appl. No 784,121 [22] Filed Dec. 16,1968 [45] Patented Dec. 15, 1970 [73] Assignee Caterpillar Tractor Co.

, Peoria, III.

a corporation of California [54] AUTOMATIC LOADER BUCKET CONTROL AND INDICATOR 1 Claim, 7 Drawing Figs.

[52] U.S.Cl 214/761, 214/764 [51] lnt.Cl E02f3/70 [50] FleldolSearch 214/762,

[56] References Cited UNITED STATES PATENTS 3,045.845 7/1962 Hackett et al. 214/761 3,234,855 2/1966 Freedy et al. 214/764X 3,429,471 2/1969 Austin et a1 2l4/764X Primary Examiner-Hugo O. Schulz Attorney-Fryer, Tjensvold, Feix, Phillips & Lempio ABSTRACT: Control and indicating means for causing a loader bucket to stop in a predetermined position after an operator has adjusted a control valve and without further attention by the operator, with moving parts that are simple and well protected from falling earth and rock which -tend to jam or damage the parts. The control includes visible indicating means to show the position of the bucket when it is hidden from the operators view.

PATENTED 05m 5 I970 SHEET 1 OF 3 F WRW NEN ER 0 N U I .N WU M MR M m 0 HJ ATTORNEYS PATENTED 115m 5 I976 SHEE'I 2 [IF 3 INVENTORS HERBERT W. BORER JOHN R. MUNTJANOFF ATTOEYS PATENTED um 519m SHEET 3 OF 3 INVENTORS HERBERT w. BORER JOHN R. MUNTJANOFF ATTORNEYS BY W 4 AUTOMATIC LOADER BUCKET CONTROL AND INDICATOR Various controls have been devised to reduce the work and increase the efficiency of loader operators. A bucket has certain more or less standard positions for different phases of its cycle such as dig, carry and dump, and controls are now in use to cause the bucket to seek these positions with as little operator effort and attention as possible.

Generally, a loader operates between a source of material and a place to deposit it such as a bin or truck. At the deposit point, the bucket is dumped by being tipped forwardly about its pivotal connection with the loader lift arms. The operator must then drive the loader back to the source position, lower the lift arms with the lift jacks and rack the bucket back to its load or dig position with the tilt jacks. It is because all of these things should be done almost simultaneously that automation has been introduced. 7

Bucket positioners have been devised which include a control valve having a detent for holding it in one operating position such as rack-back and means automatically returning it to a neutral or hold position when the bucket reaches its load position. Thus, the operator simply sets the control valve after dumping the bucket and finds the bucket in load position when he returns to the source of material.

Examples of mechanism for so controlling bucket position are disclosed in our assignees U.S. Pats. to Beck No. 3,122,247 and Erickson No. 3,289,546. These patents employ linkage which includes tubular telescoping parts operating throughout the full effective stroke of the jacks and subject to failure and damage from falling debris. Also, they do not clearly indicate the attitude of the bucket when it is obscured by material in which it is operating.

The present invention overcomes the disadvantages of presently known devices designed for much the same purpose and provides a simple low-cost device capable of positive and accurate operation.

The invention is more fully described in the following specification wherein reference is made to the accompanying drawings which show, as an example, the invention used in connection with the load position of a bucket.

In the drawings:

FIG. I is a view in side elevation of a tractor mounted loader showing the control of the present invention used in association with one of the bucket tilt jacks;

FIG. 2 is a schematic view representing the principal parts of a circuit for controlling the position ofthe bucket;

FIG. 3 is a view in side elevation of the mechanical parts of the control mechanism with a protectivecover therefor shown in section;

FIG. 4 is an enlarged fragmentary detail of some of the mechanism shown in FIG. 3;

FIG. 5 is an enlarged sectional view taken on the line V-V of FIG. 3 and with the position of the tilt jack illustrated in broken lines;

FIG. 6 is a view in plan ofthe mechanism shown FIG. 5; and

FIG. 7 is a view like FIG. 3 ofa modified form of the invention.

The tractor-mounted loader shown in FIG. 1 has a pair of lift arms 10 shown as pivotally. connected to a tractor and adapted to be raised and lowered by suitable lift jacks which are not shown. A bucket 12 is pivotally connected to the outer ends of the lift arms as at 14 and a tilt linkage generally indicated at 16 is employed for tilting the bucket about the pivots 14 between a forward dump position and a rearward carry position, the load position being the intermediate one shown in FIG. I. I

The tilt linkage includes one or more jacks shown at 18 which are extensible and retractable for moving the bucket through its range of positions. Fluid from a source under pressure may be directed selectively to opposite ends of the tilt jacks by a valve which includes a control lever 20 adjacent the tractor operator's station. When the loader reaches is its destination with the bucket in carry position the operator actuates the valve to dump the bucket and, immediately upon the contents being discharged, he operates the valve to a rackback position which directs fluid to the rod ends of the jacks for swinging the bucket rearwardly about its pivots 14. The valve is held by a detent in this position until the bucket reaches the load position shown in FIG. 1 at which time the detent means is retracted permitting the valve to return to a neutral or hold position. During this period of bucket adjustment, the operators hands and attention are free to manipulate the tractor and actuate other controls.

A simple schematic circuit for performing the above-mentioned automatic operation is shown in FIG. 2 and will be described prior to explaining the mechanical components of the control. In FIG. 2 a pump 22 is shown as directing fluid under pressure to the rod end of the jacks one of which is shown at 18. The fluid is being directed through a valve 24 actuated by the control lever 20 to be moved to the several positions of rack-back hold and dump as indicated by the letters R, H and D in FIG. 2. In the rack-back position shown fluid is exhausted from the head end of the jacks to the reservoir shown at 26. When the valve 24 is in its rack-back position a detent, shown at 28, registers with a notch or shoulder in the valve spool for retaining it in its rack-back position until the detent is released and a centering spring 30 of conventional construction returns the spool to its hold position. The detent is controlled by a piston 32, in a hydraulic cylinder which also contains a spring 34 for urging the detent toward the spool. Pressure is communicated from a line leading to the rod end of the jack 18 through a valve 36 to the rod end of the small cylinder which contains the piston 32. The valve 36 is normally closed but is opened by movement of its control lever 38 toward the left as shown in the drawings and this pressure retracts the detent 28. The valve 36 is opened by means shown in FIGS. 3 to 6 inclusive when the tilt jacks 18 have reached the position shown in FIG. 1. FIGS. 1 and 3 show a housing or protective cover 40 supported in the position adjacent and parallel to the jack 18.

An adjustable screw 42 is threaded through an opening of a bracket 44 secured for movement with the rod 46 of the jack. As the rod 46 is retracted into the cylinder the head of the adjustable screw 42 engages the end of the push rod 48 which is supported forlongitudinal movement by a roller 50 in a suitable slot in the rod and by a roller at the end of valve lever 38 in a second L shaped slot. When the push rod 48 attains a given position it moves the valve lever 38 to an upright or valveopening position shown in broken lines in FIG. 4. Meanwhile this end of the push rod is raised to the broken line position of FIG. 4 to ride on a roller 39. This permits continued leftward movement which will occur as the bucket is racked back to its carry position. When the bucket is later moved forwardly or towards its dump position the push rod 48 is retracted as by a spring shown at 52. The rear upwardly turned end 54 of the push rod 48 extends through a slot 56 in the top of the housing 40 and serves as an indicator of bucket position which is in full view of the operator's station and is particularly valuable when the bucket is buried in material in which it-is working.

The housing 40 is of inverted U-shape configuration, as shown in FIG. 5 and supported, with respect to the cylinder shown in broken lines, by bracket means one of which is shown at 58. FIGS. 5 and 6 also illustrate the configuration and arrangement of rollers 50 and the position of the roller on the end of the control lever 38 of valve 36.

A modification of the invention is shown in FIG. I wherein a straight push rod 48 has been substituted and is guided in a pair of bearings 50' which serve the purpose of the rollers and slots of the push rod 48 of FIG. 3. In this modification a cam surface 60 on the push rod 48 swings the valve lever 38' from a closed position, which is vertical as viewed in FIG. 7, to a leftward open position where it is held by the lower edge of the push rod 48' upon further leftward movement thereof. In this case the end 54' of the push rod extends beyond the housing 40, when the push rod moves toward the left, and thus comes into view to indicate the position of the bucket. A spring 52' serves the purpose of the spring 52in FIG. 3.

While the modification of FIG 7 has the advantage of simplicity particularly in the configuration of the push rod it does have bearings which may prove a disadvantage in some types of material which would cause the bearings to stick or suffer undue wear. Thus the two modifications as illustrated may be employed selectively depending upon working conditions and materials expected to be encountered.

We claim:

I. In a tractor-mounted loader which comprises a loader bucket pivoted to lift arms on the tractor and movable by a hydraulic jack from a forward position rearwardly to a second work position, a hydraulic circuit for actuating the jack, a controlvalve having an open position for directing fluid from said circuit to the jack, a spring normally closing the control valve, a detent for holding the valve in said open position, said detent spring urged toward its valve holding position and toward a retracted position by hydraulic pressure. a circuit including a normally closed valve operated by relative movement of the hydraulic jack and its piston rod for directing fluid under pressure from the jack circuit to the detent, said normally closed valve disposed adjacent the jack, a slidable push rod for opening the valve, an adjustable member on the piston rod for actuating the slidable member, a protective covering over the valve and push rod, and a part on the push rod projecting from the covering to indicate the position of the loader bucket, whereby when said bucket reaches the second work position said push rod is actuated to open said normally closed valve and hydraulic fluid is thereby directed from the jack circuit to the detent for releasing the same. 

